Commands

Configuration files must be flexible enough for any deployment need, but they must keep a clean and readable format.

Fluent Bit Commands extends a configuration file with specific built-in features. The following commands are available:

Command	Prototype	Description
@INCLUDE	@INCLUDE FILE	Include a configuration file.
@SET	@SET KEY=VAL	Set a configuration variable.

@INCLUDE

Configuring a logging pipeline might lead to an extensive configuration file. In order to maintain a human-readable configuration, split the configuration in multiple files.

The @INCLUDE command allows the configuration reader to include an external configuration file:

[SERVICE]
    Flush 1

@INCLUDE inputs.conf
@INCLUDE outputs.conf

This example defines the main service configuration file and also includes two files to continue the configuration.

Fluent Bit will respects the following order when including:

• Service

• Inputs

• Filters

• Outputs

inputs.conf

The following is an example of an inputs.conf file, like the one called in the previous example.

[INPUT]
    Name cpu
    Tag  mycpu

[INPUT]
    Name tail
    Path /var/log/*.log
    Tag  varlog.*

outputs.conf

The following is an example of an outputs.conf file, like the one called in the previous example.

[OUTPUT]
    Name   stdout
    Match  mycpu

[OUTPUT]
    Name            es
    Match           varlog.*
    Host            127.0.0.1
    Port            9200
    Logstash_Format On

@SET

Fluent Bit supports configuration variables. One way to expose this variables to Fluent Bit is through setting a shell environment variable, the other is through the @SET command.

The @SET command can only be used at root level of each line. It can't be used inside a section:

// DO NOT USE
@SET my_input=cpu
@SET my_output=stdout

[SERVICE]
    Flush 1

[INPUT]
    Name ${my_input}

[OUTPUT]
    Name ${my_output}